Journal of Environment and Earth Science                                                               www.iiste.orgISSN 2...
Journal of Environment and Earth Science                                                                   www.iiste.orgIS...
Journal of Environment and Earth Science                                                                www.iiste.orgISSN ...
Journal of Environment and Earth Science                                                                www.iiste.orgISSN ...
Journal of Environment and Earth Science                                                                www.iiste.orgISSN ...
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Journal of Environment and Earth Science                                              www.iiste.orgISSN 2224-3216 (Paper) ...
Journal of Environment and Earth Science                                              www.iiste.orgISSN 2224-3216 (Paper) ...
Journal of Environment and Earth Science                                                          www.iiste.org  ISSN 2224...
Journal of Environment and Earth Science              www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No...
Journal of Environment and Earth Science                                                                                  ...
Journal of Environment and Earth Science                                                                               www...
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Engineering geophysical investigation around ungwan doka, shika area within the basement complex of north western nigeria.

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Engineering geophysical investigation around ungwan doka, shika area within the basement complex of north western nigeria.

  1. 1. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012 Engineering Geophysical Investigation Around Ungwan Doka, Shika Area within the Basement Complex of North-Western Nigeria ⃰ FADELE S.I (M.Sc), JATAU B.S (Ph.D) AND UMBUGADU A. (M.Sc) Nasarawa State University, Keffi, Nigeria ⃰ Email: fadeleidowu@yahoo.com +2348066035524; bsjatau@yahoo.co.uk +2348034529326AbstractGeophysical investigation for engineering or environmental studies was carried out around Ungwan Doka ofShika area which falls within the Basement Complex of North-Western Nigeria. The study is aimed at evaluatingthe competence of the near surface formation as foundation materials, and to unravel the subsurface profilewhich in turn determines if there would be any subsurface lithological variation(s) that might lead to structuralfailure at the site and evaluating the groundwater potential of the site and determining the level of safety of thehydrogeologic system. Vertical Electrical Sounding (VES), using Schlumberger configuration was adopted. Atotal of 18 VES was conducted. The data obtained were subjected to 1-D inversion algorithm to determine thelayer parameters. The geoelectric section revealed two to four lithologic units defined by the topsoil, whichcomprises clayey-sandy and sandy lateritic hard pan; the weathered basement; partly weathered/fracturedbasement and the fresh basement. The resistivity values range from 26 m - 373 m; 77 m - 391 m; 473 m -708 m; and 1161 m - 3600 m in the topsoil, weathered, fractured basement and fresh basement respectively.Layer thicknesses vary from 0.38m – 6.58m in the topsoil, 1.1m – 33.04m in the weathered layer, 5.86m – 34.1min the fractured basement. Depth from the surface to bedrock/fresh basement generally varied between 2.65mand 37.75m. Based on the resistivity values, it is concluded that the subsurface material up to the depth of 25m iscompetent and has high load-bearing capacity. However, resistivity values less than 100 m at depths of10m-15m indicate high porosity, high clayey sand content and high degree of saturation which are indications ofsoil conditions requiring serious consideration in the design of massive engineering structures. Thehydrogeologic system at the site is vulnerable to contamination. Hence, the result reasonably provide a basis forwhich groundwater potential zones are appraised for safety in case potential sources of groundwatercontamination sites such as septic tanks and sewage channels are planned for the area under study.Key words: VES, Top soil, Weathered Basement, Partly weathered or Fractured Basement, Fresh ,Basement1. IntroductionThe failure statistic of structures such as buildings, tarred roads and bridges throughout the nation is increasinggeometrically. Most of these failures were caused by swelling clays (Blyth and Freitas, 1988). In recent times,the collapse of civil engineering structures has been on the increase for reasons associated with subsurfacegeological sequence (Omoyoloye et al., 2008). The foundation of any structure is meant to transfer the load ofthe structure to the ground without causing the ground to respond to uneven and excessive movement. In order toachieve this, most buildings are supported on pads, strips and rafts or piles (Blyth and Freitas, 1988). Thereforethe knowledge of the probable cause of rampant failure of building foundations due to subsurface movementsgiving rise to cracks or structural differential settlements has been a great concern to geoscientists. This hashelped to distinguish between a continuing movement, which is often more likely to be a problem and those ofsingle events, which may not require repair depending on the extent of damage. However, adequate insight onthe types and patterns of foundation-based cracks and their evaluation has necessitated the need to consider thegeological and geophysical basis for buildings’ failure and adequate precaution taken to minimize such disaster.The amount, type and direction of foundation movement are commonly noted from the bulging of brick ormasonry blocks. These in turn reveal the risk of vertical collapse or horizontal dislocation. The risk could betraced to the height of construction, materials used for the building, site factor, earth loading or water. Otherfactors include the seismic action, atmospheric disaster and accident (Omoyoloye et al., 2008). If cracks are oldwith no sign of continuing or recurrent movement, building inspectors accept monitoring rather than quicklyrecommending repairs. Most house settling cracks are basically caused by either the differences in expansion andcompression coefficients of the construction materials, relative changes in the shapes and sizes of saturated soilsor the dynamic earth. The need for subsurface geophysical investigation has therefore become very imperative soas to prevent loss of valuable properties and lives that always accompany such a failure. Foundation evaluationof a new site is necessary so as to provide subsurface and aerial information that normally assist civil engineers,builders and town planners in the design and siting of foundations of civil engineering structures (Omoyoloye, etal., 2008). Geophysical methods such as the Electrical Resistivity (ER), Seismic refraction, Electromagnetic 17
  2. 2. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012(EM), Magnetic and Ground Penetrating Radar (GPR) are used singly or in combinations for engineering siteinvestigations. The applications of such geophysical investigation are used for the determination of depth tobedrock, structural mapping and evaluation of subsoil competence (Burland and Burbidge, 1981; Burger, 1992).The engineering geophysical investigation was carried out at Ungwan Doka in Shika area, Kaduna State,North-Western Nigeria, aimed at determining the depth to the competent stratum in the subsurface, delineationof areas that are prone to subsidence or some form of instability, evaluating the groundwater potential of the siteand determining the level of safety of the hydrogeologic system in the study area.2. Location and Topography of the Study areaThe study area lies between Latitudes 110 10’ 49”N - 110 11’ 05” N and Longitudes 70 35’40”E - 70 38’ 50” E.The site is situated along the Sokoto road, North West of Zaria (Fig. 1). The topography is that of high plain (flatterrain) of Hausa land. The site is located within the tropical climatic belt with Sudan Savannah vegetation. Theenvironment is Savannah type with distinct wet and dry season. The rainfall regime is simple but with slightvariation which consists of wet season lasting from May to September and characterized by heavy down pour atthe start and end of the rainy season. The annual rainfall varies between 800 mm to 1090 mm while the meanannual temperature ranges between 240C to 310C reaching a maximum of about 360C around April (Hore,1970;Goh and Adeleke, 1978).3. Geology of Study AreaThe study area is laid on undifferentiated Basement Complex. Though there were no rock out-crops within thesite, observation however revealed that the weathered bedrock in some existing hand-dug wells within the siteand environs indicates the occurrence of granitic rocks within the site which are porphiritic in texture. The studyarea falls within the Metasediments of the Basement Complex (McCurry, 1970). The Basement Complex inKaduna state was affected by an Orogeny, which predated the emplacement of the Older Granite. During thisevent, deformation of the basement produced north-south trending basins of Metasediment in the form ofSynclinoria. Tertiary earth movements tilted the Metasediments to north and warped the basement along the axisof the uplift pass through the present Kaduna state having northwest trend. They have a pronounced effect on thedrainage pattern of the state. Through the process of metamorphism, migmatization and granitization thatoccurred within at least two tectono-metamorpic cycles, the rocks were largely transformed into migmatites andgranite gneiss, with some relics of the original gneisses McCurry (1976). The Basement Complex was laterintruded by series of intermediate and acid plutonic rocks during the Pan African Orogeny according to McCurry(1976). Oyawoye (1970), showed that there is structural similarity between the study area and the rest of WestAfrica. (MacLeod et al 1971), reported that newer basalts often overlie alluvial deposits. The Younger Granitesare high level discordant intrusions in the Basement Complex and occupy approximately 8% of the total surfacearea of Nigeria according to Rahaman (1976).4. MethodologyVertical Electrical Soundings (VES) using Schlumberger array were carried out at eighteen (18) stations. Aregular direction of N-S azimuth was maintained in the orientation of the profiles. Overburden in the basementarea is not as thick as to warrant large current electrode spacing for deeper penetration (Oseji, et al., 2005;Okolie, et al., 2005), therefore the largest Current electrode spacing AB used was 200m, that is, 1/2AB=100m.The principal instrument used for this survey is the ABEM (Signal Averaging System, (SAS 300) Terrameter.The resistance readings at every VES point were automatically displayed on the digital readout screen and thenwritten down on paper.5. Results and DiscussionShlumberger array shown in figure 2 was adopted for the survey. A and B are point current electrodes throughwhich current is driven into the ground, while M and N are two potential electrodes to record the potentialdistribution in the subsurface within the two current electrodes.From Ohm’s law, the current I and potential V in a metal conductor at constant temperature are related asfollows: V = IR (1)Where R is the constant of proportionality termed resistance and it is measured in ohms. The resistance R, of aconductor is related to its length L and cross sectional area A by; R = ρL / A (2) 18
  3. 3. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012Where ρ is the resistivity and it is a property of the material considered.From equation (1) and (2), V = IρL / A (3)The vertical electrical sounding (VES) with Schlumberger array involves fixing the potential electrodes at pointM and N, and symmetrically increasing the current electrode separation AB about the centre by displacing A andB outwardly in steps. This will increase the depth of penetration within the separation AB. Thus the varyingresistivity measured when electrode array position is varied in an inhomogeneous medium is termed apparentresistivity.For simple treatment, a semi-infinite solid with uniform resistivity, ρ, is considered. A potential gradient ismeasured at M and N when current electrodes located on the surface of the equipotential surface is semi-spheraldownward into the ground at each electrode. The surface area will then be 2πL2, where L is the radius of thesphere. Thus V = Iρ / 2πL (4)By deduction then, the potential at M (VM), due to the two current electrodes, is VM = Iρ/{2π (1/r1 – 1/r2)} (5)Similarly, the potential at electrode N (VN) is given by VN = Iρ/{2π (1/r3 – 1/r4)} (6)where r1, r2, r3 and r4 are shown in Figure 2.The potential difference, ∆V, acrss electrodes M and N is VM – VN. If the body is inhomogeneous like the studyarea, apparent resistivity (ρa) is considered, ρa = K (∆V/ I) (7)Where ρa is apparent resistivity in ohm-metre, and K = 2π [(1/r1 – 1/r2) - (1/r3 – 1/r4)] -1 (8)K is called the geometric factor whose value depends on the type of electrode array used.For Schlumberger array, if MN =2b and 1/2AB = L then, K = π (L2/2b – b/2) (9)The geometric factor, K, was first calculated for all the electrode spacings using the equation 9; K= π (L2/2b –b/2), for Schlumberger array with MN=2b and 1/2AB=L. The values obtained, were then multiplied with theresistance values to obtain the apparent resistivity, ρa, values (equation 7). Then the apparent resistivity, ρa,values were plotted against the electrode spacings (1/2AB) on a log-log scale to obtain the VES sounding curvesusing an appropriate computer software IPI2win in the present study. Some sounding curves and their models areshown in Fig.3. Similarly, geoelectric sections are shown in Figs. 4 and 5.Three resistivity sounding curve typeswere obtained from the studied area and these are the H (ρ1>ρ2<ρ3), A (ρ1< ρ2<ρ3) and KH (ρ1>ρ2< ρ3>ρ4) typecurves. However, there are few points which show two geologic layer cases. The results of the interpreted VEScurves are shown in Tables 1 and 2. The modeling of the VES measurements carried out at eighteen (18) stationshas been used to derive the geoelectric sections for the various profiles (Figure 4 and 5). These have revealedthat there are mostly four and three geologic layers beneath each VES station, and two layer cases at threedifferent VES points. The geologic sequence beneath the study area is composed of top soil, weatheredbasement, partly weathered/fractured basement, and fresh basement. The topsoil is composed of clayey-sandyand sandy-lateritic hard crust with resistivity values ranging from 26 m to 391 m and thickness varying from0.38m to 6.58m, thinnest at VES 12 and thickest at VES 13. It is however, observed from the geoelectricsections that VES 10, 11, 12 and 13 are characterized with low resistivity values varying between 26 m to99 m suggesting the clayey nature of the topsoil in these areas and possibly high moisture content. The secondlayer is the weathered basement with resistivity values varying from 77 m to 391 m and thickness rangesbetween 1.1m to 33.04m, thinnest at VES 16 and thickest at VES 6. The third layer is the partly weathered andfractured basement with resistivity and thickness values varying between 473 m to 708 m and 5.86m to 34.1m 19
  4. 4. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012respectively. The layer is extensive and thickest at VES 18 and thinnest at VES 16. The fourth layer ispresumably fresh basement whose resistivity values vary from 1161 m to 3600 m with an infinite depth.Though the thickness of the bedrock is assumed to be infinite, the depth from the earth’s surface to the bedrocksurface varies between 2.65m to 37.75m. Quite a few of the profiles dipping and a negligible number of themshow synclinal and fractured structure. These formations have some geological, physical and near-surfaceengineering significance.6.1 Profile A-A’Profile A-A’ geoelectric section suggests that the site is characterized by lateritic hard pan at differentconsolidation levels within shallow depths, while gneiss and granites mainly, characterize the basements (Fig.4).The fresh basements have synclinal structure which cut across the profile. The weathered/fractured basement hasa dipping layering. The probable feature that may cause building failure could be geologic feature like dippingbedrock or synclinal structure. This is because while overburden materials fill the synclinal structure, theircolumns undergo ground movement by subsidence and thereby could amount to uneven settlement at thefoundation depths of buildings. In other words, uneven stress distribution may occur at the foundation depths ofsubsurface, that is one side of building structure may have a stronger support than the other adjacent of it.Another factor that could contribute to structural defect of building is the seasonal variation in the saturation ofclay which causes ground movement and is caused by clay swells and shrinkages which are occasioned byalternate wet and dry seasons. The area is characterized by clay soils with lateritic patches at shallow depths withtheir thickness ranging between 1.06m and 4.14m.6.2 Profile B-B’The geoelectric section revealed clayey sandy topsoil having some lateritic hard crust patches (Fig. 5). Thesynclinal structure at VES point 11 is not well pronounced and may not pose any serious danger to buildingfoundation. However, there is a deep weathering beneath VES point 17 and 18. The presence of laterite beneaththe clayey topsoil which hardly extends beyond 2.5m reduces the danger posed by clay formation to largebuildings. This area forms a good site for the erection of high-rise civil engineering structures.6.3 Competence EvaluationThere are no indications of any major linear structure such as fracture or faults that could aid buildingsubsidence. The geologic sequence beneath the area is composed of thin layer of topsoil, thick weathered layer,partly weathered/fractured basement and fresh bedrock. The topsoil constitutes the layer within which small civilengineering structures can be constructed. From the table of resistivity values Table 1, the topsoil is composed ofsandy clay, clayey sand and patches of lateritic hard pans. Engineering competence of the subsurface can bequalitatively evaluated from the layer resistivity. The higher the layer resistivity value, the higher thecompetence of a layer; hence from the point of view of the resistivity value therefore, laterite is the mostcompetent of the delineated topsoil, followed by clayey sand and sandy clay being the least competent. Based onthe resistivity values, depths of about 8-10m can support small to medium size structures while depth in excessof 25m can support massive civil engineering structures in the study area.6.4 Groundwater PotentialEven though experience has shown that there is no direct relationship between groundwater yield and boreholedepth in a basement complex environment, studies (Bala and Ike, 2001; Omosuyi et al., 2008; Ariyo andOsinawo, 2007) revealed that areas with thick overburden cover in such basement complex terrain has highpotential for groundwater. According to Ariyo and Oguntade (2009), in a basement complex terrain, areas withoverburden thickness of 15m and above are good for groundwater development. The highest groundwater yieldis often obtained from a weathered/fractured aquifer, or simply a subsurface sequence that has a combination ofa significantly thick and sandy weathered layer and fractured aquifer. Where the bedrock is not fractured, aborehole can be located at a point having a relatively high layer resistivity greater than 150 m but less than600 m (Olorunfemi, 2009). From the foregoing two parameters – overburden thickness and resistivity values,VES 1, 2, 3, 4, 5, 6, 7, 17 and 18 can be considered to be productive zones for groundwater development in thestudy area. Since the area is generally shallow to the water aquifer and groundwater in this area is vulnerable topollution, the depth of sewage system should be <10m to the weathered basement (aquiferrous zone) in order toavoid groundwater contamination. It is suggested that potential sources of contamination site like sewagechannels should be sited far away from viable aquifer units to ensure safety consumption of groundwater withinthe area.7. ConclusionThe VES results revealed heterogeneous nature of the subsurface geological sequence. Though the geoelectricsection showed complexity in the subsurface lithology, there is however, no indication of any majorfracture/fault that could aid subsidence. The geologic sequence beneath the study area is composed of topsoil, 20
  5. 5. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012weathered layer, partly weathered/fractured basement, and fresh basement. The topsoil is composed ofclayey-sandy and sandy-lateritic hard crust with resistivity values ranging from 26 m to 391 m and thicknessvarying from 0.38m to 6.58m, thinnest at VES 12 and thickest at VES 13. It is however, observed from thegeoelectric sections that VES 10, 11, 12 and 13 are characterized with low resistivity values varying between26 m to 99 m suggesting the clayey nature of the topsoil in these areas and possibly high moisture content.The second layer is the weathered basement with resistivity values varying from 77 m to 391 m and thicknessranges between 1.1m to 33.04m, thinnest at VES 16 and thickest at VES 6. The third layer is the partlyweathered and fractured basement with resistivity and thickness values varying between 473 m to 708 m and5.86m to 34.1m respectively. The layer is extensive and thickest at VES 18 and thinnest at VES 16. The fourthlayer is presumably fresh basement whose resistivity values vary from 1161 m to 3600 m with an infinitedepth. Though the thickness of the bedrock is assumed to be infinite, the depth from the earth’s surface to thebedrock surface varies between 2.65m to 37.75m. A-curve type which shows a continuous and uniform increasein resistivity predominates. This curve typifies an area showing characteristics of high load-bearing strength.This is followed by HK-curve showing that some areas have overburden saturation which recharges the mainaquifer units. The rest of the curves are minority in number with H-type curve which has a minimum resistivityintermediate layer underlain and overlain by more resistant materials reminiscent of areas promising forgroundwater development and also few 2-layer cases close to the bedrock are observed. Based on the resistivityvalues of the different geoelectric layers, the various geologic units up to depth of 25m are competent and cansupport massive civil engineering structures. The presence of laterite beneath the clayey topsoil which hardlyextends beyond 2.5m reduces the danger posed by clay formation to large buildings. Other probable causes offoundation defects are the growth of tree roots, organic deposits, sink holes, cavities or ground surface saturationdue to seepages and this should be taken care of during building project implementation to ensure that buildingserected at the site stands the test of time. In a basement complex terrain, areas with overburden thickness of15m and above are good for groundwater development. The highest groundwater yield is often obtained from aweathered/fractured aquifer, or simply a subsurface sequence that has a combination of a significantly thick andsandy weathered layer and fractured aquifer. Where the bedrock is not fractured, a borehole can be located at apoint having a relatively high layer resistivity greater than 150 m but less than 600 m (Olorunfemi, 2009).From the foregoing two parameters – overburden thickness and resistivity values, VES 1, 2, 3, 4, 5, 6, 7, 17 and18 can be considered to be productive zones for groundwater development in the study area. To ensure safetyappraisal of groundwater consumption in the area, potential sources of contamination site should be sited faraway from viable aquifer units to ensure safety consumption of groundwater within the study area.AcknowledgementThe field guide and contributions of Dr. B.S Jatau technically and financially cannot be over emphasized. Hissupports, corrections and guides are gratefully acknowledged, you are indeed a good mentor. Words of wisdomand encouragement from my fathers and mentors in geology matters, the likes of Prof. S. Abaa and Prof. N.G.Obaje also make this paper work a huge success. 21
  6. 6. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012ReferencesAriyo, S.O. and Oguntade, A.K. (2009). Geophysical Investigation for Groundwater Potential in Mamu Area, Southwestern Nigeria. Medwell Online Journal of Earth Sciences, Vol.3, no.1, pp.10-13.Ariyo, S.O. and Osinawo, O.O. (2007). Hydrogeophysical Evaluation of Groundwater Potentials of Atan/Odosenbora. Medwell Online Journal of Earth Sciences, Vol.9, no.1, pp. 50-65.Bala, A.E. and Ike, E.C. (2001). The Aquifer of the Crystalline Basement Complex Area of Africa. Quarterly Journal of Engineering Geology, Vol.18, pp. 35-36.Burger, R.H (1992), ‘Exploration Geophysics of the Shallow Subsurface’. Prentice Hall, U.S.A. pp. 30-56Blyth, F.G.H and de Freitas, M.D., (1988). Geology for Engineers. Butler and Tannar Ltd, Frome and London. Pp. 292-293.Burland, J.B and Burbidge, M.C (1981). Settlement of Foundations on Sand and Gravel Proceedings of the Institution of Civil Engineers, 78(1), pp. 1325- 1381.Goh, C.L., and Adeleke, B.O., (1978). Certificate Physical and Human Geography’ Oxford University Press, Ibadan,pp78-150.Hore, P.N (1970). Weather and Climate of Zaria and its Region. (Ed.) By M.J. Mortimore, Department of Geography, Occasional Paper No4. A.B.U. Zaria. pp. 41-54McCurry, P. O. (1970). The Geology of Zaria sheet 102 S.W and its Region in Mortimore, M.J. (Ed). Department of Geography occasional paper No.4, Ahmadu Bello University, Zaria. pp. 1-3.McLeod W.N.; Turner D.C. and Wright, E.P. (1971). The Geology of Jos Plateau with 1:100,000 Sheets 147,148,168,169,189 and 190. Geol. Survey Nigeria Bulletin, 32.Omosuyi, G.O., Ojo, J.S. and Enikanoselu, P.A. (2003). Geophysical Investigation for Groundwater around Obanla-Obakekere in Akure Area within the Basement Complex of South-western Nigeria. Journal of Mining and Geology, Vol.39, no.2, pp. 109-116.Okolie, E.C., Osemeikhian, J.E.A., Oseji, J.O. and Atakpo, E. (2005). Geophysical Investigation of the Source of River Ethiope in Ukwuani Local Government Area of Delta State. Nigerian Institute of Physics, Vol.17, pp.30-45.Olorunfemi M.O. (2009). Water resources, Groundwater Exploration, Borehole site selection, and Optimum Drill Depth in Basement Complex Terrain: Journal of the Nigerian Association of Hydrogeologists. Special Publication Series 1, pp. 1-20.Omoyoloye, N.A., Oladapo, M.I. and Adeoye, O.O., (2008). Engineering Geophysical Study of Adagbakuja Newtown Development, Southwestern Nigeria. Medwell Online Journal of Earth Science; Vol. 2(2); pp. 55-63Oseji, J.O., Atakpo, E. and Okolie, E.C. (2005). Geoelectric Investigation of the Aquifer Characteristics and Groundwater Potential in Kwale, Delta State. Nigerian Journal of Applied Sciences and Environmental Management, Vol.9, pp. 157-1600.Oyawoye, M.O (1970). The Basement Complex of Nigeria. In: Dessauvagie, TFJ and White man, A.J (Eds) African Geology. University Press, Ibadan Nigeria pp. 91-97.Rahaman, M.A. (1976).Review of the Basement Geology of South western Nigeria. In: Kogbe (Ed.). Geology of Nigeria, Elizabeth Publishing Company Lagos pp 41-58. 22
  7. 7. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012 Figure 1: Location Map Showing the Study Area (From Northern Nigerian Survey Map) Study Area 23
  8. 8. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012 Table 1: The results of the interpreted VES curves 24
  9. 9. Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol 2, No.7, 2012 r1 r2Earth’s surface A M N B r3 r4 Figure 2: Four-general electrode configuration (Shlumberger Array). 25
  10. 10. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 2, No.7, 2012 26
  11. 11. Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol 2, No.7, 2012 VES VES 2 VES 4 VES VES VES VES 8 VES 9 1 VES 3 5 6 7 A A’ 373 ࢹ࢓ 370 ࢹ࢓ 276 ࢹ࢓ 304 ࢹ࢓ 365 ࢹ࢓ 353 ࢹ࢓ 257 ࢹ࢓ 272 ࢹ࢓ 367 ࢹ࢓ ૛૛૚ ࢹ࢓ 59 ࢹ࢓ 708ߗ݉ 298 ࢹ࢓ 351 ࢹ࢓ 228 ࢹ࢓ 77 ࢹ࢓ 10 3115 ࢹ࢓ 1765 ࢹ࢓ 144 ࢹ࢓ 391 ࢹ࢓DEPTH (m) 473 ࢹ࢓ 20 834 ࢹ࢓ 522 ࢹ࢓ 1362 ࢹ࢓ 503 ࢹ࢓ 30 1251 ࢹ࢓ 1410 ࢹ࢓ 1450 ࢹ࢓ 40 Lateritic hard pan (Top soil) Weathered layer Partly weathered/fractured layer Fresh basement 27
  12. 12. Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol 2, No.7, 2012 Figure 4: Geoelectric section along profiles A-Ai VES 10 VES 11 VES 12 VES 13 VES 14 VES 15 VES 16 VES 17 VES 18 B’ B 28 ࢹ࢓ 281 ࢹ࢓ 256 ࢹ࢓ 26 ࢹ࢓ 28 ࢹ࢓ 30 ࢹ࢓ 30 ࢹ࢓ 254 ࢹ࢓ 316 ࢹ࢓ 347 ࢹ࢓ 358 ࢹ࢓ 356 ࢹ࢓ 261 ࢹ࢓ 162 ࢹ࢓ 199 ࢹ࢓ 519 ࢹ࢓ 694 ࢹ࢓ 302 ࢹ࢓ 3699 ࢹ࢓ 2593 ࢹ࢓ 3307 ࢹ࢓ 1270 ࢹ࢓ 2935 ࢹ࢓ 10 1519 ࢹ࢓ 658 ࢹ࢓ 1410 ࢹ࢓DEPTH (m) 20 30 1614 ࢹ࢓ 40 3511 ࢹ࢓ Clay/clayey sandy (Top soil) Lateritic hard pan (Top soil) Weathered layer Partly weathered/fractured layer Fresh basement Figure 5: Geoelectric section along profiles B-Bi 28
  13. 13. This academic article was published by The International Institute for Science,Technology and Education (IISTE). The IISTE is a pioneer in the Open AccessPublishing service based in the U.S. and Europe. The aim of the institute isAccelerating Global Knowledge Sharing.More information about the publisher can be found in the IISTE’s homepage:http://www.iiste.orgThe IISTE is currently hosting more than 30 peer-reviewed academic journals andcollaborating with academic institutions around the world. Prospective authors ofIISTE journals can find the submission instruction on the following page:http://www.iiste.org/Journals/The IISTE editorial team promises to the review and publish all the qualifiedsubmissions in a fast manner. All the journals articles are available online to thereaders all over the world without financial, legal, or technical barriers other thanthose inseparable from gaining access to the internet itself. Printed version of thejournals is also available upon request of readers and authors.IISTE Knowledge Sharing PartnersEBSCO, Index Copernicus, Ulrichs Periodicals Directory, JournalTOCS, PKP OpenArchives Harvester, Bielefeld Academic Search Engine, ElektronischeZeitschriftenbibliothek EZB, Open J-Gate, OCLC WorldCat, Universe DigtialLibrary , NewJour, Google Scholar

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